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Biomedical subjects

J R Standen

Publications and source records attributed to J R Standen.

15 recordsLinked to original sources
PubMed2001

The solitary pulmonary nodule on chest radiography: can we really tell if the nodule is calcified?

OBJECTIVE: This study was designed to assess the ability of radiologists to accurately detect calcification within a solitary pulmonary nodule with chest radiography. MATERIALS AND METHODS: Thirty-five solitary pulmonary nodules that were examined by both posteroanterior and lateral chest radiography and on thin-section CT were retrospectively identified. Fourteen radiologists blinded to the results of CT assessed the nodules for the presence or absence of calcification using chest radiographs alone. The radiologists then assigned one of six values on the basis of their confidence in that assessment. The accuracy and confidence values for each nodule were analyzed on the basis of the presence or absence of calcification as seen on CT. Receiver operating characteristic (ROC) curves were generated. RESULTS: The positive predictive value of a "definitely calcified" assessment was 0.93. Combining all levels of radiologists' confidence, the sensitivity of the chest radiograph in the detection of calcium was 0.50 and the specificity was 0.87. There was no difference in the confidence levels reported between the calcified and noncalcified nodules, and there was no correlation of nodule size with accuracy or confidence level. CONCLUSION: The ability of radiologists to detect calcium in a solitary pulmonary nodule by chest radiography was low, as defined by the ROC data. Of the "definitely calcified" nodules, up to 7% may not be calcified and may be potentially malignant. Without documentation of long-term stability, a low threshold for recommending CT may be appropriate.

Aged↗
PubMed1998

Influence of image processing on chest radiograph interpretation and decision changes.

RATIONALE AND OBJECTIVES: The authors investigate the effect of image processing on diagnostic performance in the reading of computed chest radiographs. MATERIALS AND METHODS: Six radiologists read 168 chest images with and without the use of image processing. Diagnostic performance was measured by means of receiver operating characteristic analysis, and changes made in diagnostic decisions with the use of image processing were evaluated. RESULTS: There were no statistically significant differences between reader performance with image processing and reader performance without image processing (P < .05). Readers' decisions were just as likely to change from false-negative to true-positive as from true-positive to false-negative with the use of image processing. More decisions changed from true-negative to false-positive than from false-positive to true-negative with processing, CONCLUSION: The effect of image processing does not greatly influence diagnostic performance in chest radiography.

Attitude of Health Personnel↗
PubMed1994

Receiver operating characteristic evaluation of computer display of adult portable chest radiographs.

RATIONALE AND OBJECTIVES: The suitability of using an image console monitor for interpretation of adult portable chest radiographs was evaluated with receiver operating characteristic (ROC) analysis and subjective techniques. METHODS: Radiologists read 80 chest images, once on a display monitor and once on computed radiography film, for the presence or absence of pneumothorax or atelectasis. Judgments of correct or incorrect positions of tubes and lines were reported, and total viewing time was recorded. RESULTS: A statistically significant difference was found in favor of monitor reading for detection of pneumothoraces. Atelectasis detection also was higher with monitor reading, but the difference did not reach statistical significance. Tube/line judgments were equivalent for both modes. Total viewing time was approximately 1 minute longer per image with the monitor. CONCLUSIONS: Viewing computed radiography images on a workstation monitor does not seem to affect diagnostic accuracy compared with film viewing. Preset image defaults tailored to the individual radiologist could decrease total viewing time to acceptable levels.

Adult↗
PubMed1994

Prospective comparison of use of the laryngeal mask and endotracheal tube for ambulatory surgery.

We examined the response to the laryngeal mask (LM) compared to the endotracheal tube (ETT) in patients undergoing ambulatory anesthesia. The differences in management by the anesthesiologists for these two airways were also examined. Peripheral orthopedic procedures were studied in 44 outpatients randomized to receive a LM or ETT, and either spontaneous or controlled ventilation. Anesthesia was induced with propofol and succinylcholine intravenously (i.v.) and maintained with N2O and isoflurane. Anesthesiologists were allowed to determine ventilatory variables and anesthetic concentration. Hemodynamic and ventilatory measurements were made during the anesthesia. Barium sulfate was poured into the oropharynx after the airway was secure. Fiberoptic examination through the LM was performed at the beginning and at the end of the administration of each anesthetic. Radiographs were taken at the end of the anesthetic administration before LM or ETT removal to look for barium in the trachea. After airway removal, presence of blood on the airway, sore throat, coughing, nausea, vomiting, shivering, and amount of morphine demanded during recovery were noted. No barium in the trachea or bronchial tree was seen in any of the radiographs. The ETT was associated with greater hemodynamic response not only to airway placement (P < 0.05), but also to surgical incision (P < 0.05) and airway removal (P < 0.05). Spontaneous or controlled ventilation favored neither airway, although the ETT was associated with increased work of inspiration with controlled ventilation (P < 0.05). Anesthesiologists tended to elect smaller tidal volumes, faster ventilation rates, and lower anesthetic concentrations for patients with the LM (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Bedside cardiovascular examination in patients with severe chronic heart failure: importance of rest or inducible jugular venous distension.

OBJECTIVES: The aim of this study was to determine the sensitivity, specificity and utility of the cardiovascular examination in predicting cardiac hemodynamics in patients with advanced chronic congestive heart failure. BACKGROUND: Although the physical signs of acute left heart failure have been shown to correlate relatively well with cardiac hemodynamics, their reliability in estimating hemodynamics in patients with chronic heart failure has recently been questioned. METHODS: We prospectively recorded the history, cardiovascular physical signs present at bedside examination and the hemodynamic measurements obtained at right heart catheterization in 52 patients with chronic congestive heart failure undergoing in-hospital evaluation for possible heart transplantation. In addition, we obtained chest radiographs and multigated nuclear scans for the evaluation of left ventricular function. RESULTS: Pulmonary rales, a left ventricular third heart sound, jugular venous distension and the abdominojugular test, when positive, indicated higher right heart pressures and lower measures of cardiac performance. The presence of jugular venous distension, at rest or inducible, had the best combination of sensitivity (81%), specificity (80%) and predictive accuracy (81%) for elevation of the pulmonary capillary wedge pressure (> or = 18 mm Hg). Furthermore, in this population sample, the probability of an elevated wedge pressure was 0.86 when either variable was present. CONCLUSIONS: The bedside cardiovascular examination in the patient with chronic heart failure is extremely useful in identifying patients with elevation of right and left heart pressures. Examination for jugular venous distension at rest or by the abdominojugular test is simple and highly sensitive and specific in assessing left heart pressures in these patients.

Adult↗
PubMed1991

Expiratory computed tomography for assessment of suspected pulmonary emphysema.

Results of computed tomography of the lung performed at two levels in upper lung zones at full inspiration and full expiration were compared with results of tests of ventilatory function, lung mechanics, and single breath carbon monoxide diffusing capacity in 64 subjects, many of whom had some form of airflow obstruction. From the CT scans, the mean percentage of pixels in the range -900 to -1,024 Hounsfield units, or pixel index, was determined for each subject. The highest correlations of pixel index with physiologic variables consistent with a diagnosis of emphysema were observed for CT taken at full expiration. In some subjects, the inspiratory CT would give a "false positive" for emphysema when the hyperaeration observed at inspiration was not observed at expiration. We believe that the CT scan taken at full expiration can effectively reveal the abnormal permanent enlargement of airspaces which defines emphysema and provides a noninvasive method of assessing lung morphology in the living human subject.

Adult↗
PubMed1988

Radiologic appearance of the Jarvik artificial heart implant and its thoracic complications.

The principles of total artificial heart devices, their radiologic appearance, and the complications associated with their use have become increasingly relevant as these devices are used more often in patients with end-stage cardiac disease. The Jarvik artificial heart implant is the one used most frequently. Intrathoracic complications related to its use were evaluated radiographically in seven patients undergoing implantation at our institution. Because of the relatively large size of the device, complications from compression of the left lung are common. Four of the seven patients had prolonged atelectasis of the left lower lobe and two had major vascular compression (pulmonary veins in the left lung in one and the inferior vena cava in another). Other chest complications were infection in the surgical site (three patients), mediastinal bleeding (one patient), and extensive fibrous adhesions around the device, making explantation difficult (one patient). All seven patients had pulmonary edema before surgery, which regressed over several days after surgery. Radiographs readily display the major components of the Jarvik heart and are valuable for detecting pulmonary complications associated with its use.

Adult↗
PubMed1983

Ultrasonographic assessment of hydronephrosis of pregnancy.

We examined 100 consecutive patients presenting for gestational assessment by ultrasonography for hydronephrosis. Hydronephrosis in these patients was assessed in respect of its incidence, degree, laterality, and its relation to stage of gestation. Hydronephrosis was found to be present in approximately half of our patients particularly in the second and third trimesters. Hydronephrosis was more prevalent on the right than on the left side. We believe that hydronephrosis of pregnancy is physiologic and that both mechanical and hormonal factors contribute to its occurrence.

Female↗
PubMed1978

Renal arteriography in von Hippel-Lindau Diease.

Since 1960, 17 patients with von Hippel-Lindau disease have had cerebellar hemangioblastomas removed at the Victoria General Hospital, Halifax, Nova Scotia. The 4 most recent patients have had renal arteriography as a part of their investigation. Though 3 of these had negative urography, all 4 had positive findings on arteriography. The first patient had bilateral renal cell carcinomas and cysts and failed to respond to 1 year of 'Laetrile' therapy; the second had small cysts in each kidney; the third had bilateral renal cysts, multiple left renal cell carcinomas and a clinically unsuspected right pheochromocytoma; the fourth had a small renal cell carcinoma. It is recommended that all patients with von Hippel-Lindau disease and siblings with any manifestations of the disease have renal arteriography as part of their early investigation.

Adenocarcinoma↗
PubMed1977

Angiography in gastointestinal bleeding.

Over a four-year period, eight patients with documented gastrointestinal bleeding had angiography as a part of their investigation and treatment at the Department of Radiology, Victoria General Hospital, Halifax, Nova Scotia. A review of these eighty cases has been carried out and angiography has been found to be both safe and reliable in the diagnosis of gastrointestinal bleeding. Cautiously administered intra-arterial pitressin infusion therapy will arrest bleeding in about one-third of cases and in most others will reduce blood loss so that a critically ill patient may be made more fit for subsequent surgery. Patients who have recently received intravenous pitressin should not be given intra-arterial pitressin.

Aged↗
PubMed1977

Arteriography in malignant neoplasms of the bowel.

Eighty patients with gastrointestinal bleeding were investigated by angiography over a four-year period. Nine had malignant neoplasms of the bowel. Inconspicuous neovascularity was the most constant finding, best seen in leiomyosarcoma of the small bowel and adenocarcinoma of the colon. Neovascularity was not seen in a patient with reticulum cell sarcoma of colon detected by extravasation. When other studies including endoscopy and barium examinations have failed to explain acute or chronic bleeding, an appreciable number of intestinal neoplasms may be demonstrated by arteriography.

Adenocarcinoma↗
PubMed1975

"Tumor vascularity" in left atrial thrombus demonstrated by selective coronary arteriography.

Coronary arteriography was performed during preoperative investigation of mitral valve disease in a 62-year-old woman. "Vascular puddles" arising from the left coronary artery were seen within a large filling defect in the left atrium, raising the suspicion of myxoma. At surgery, the filling defect proved to be partially organized thrombus. "Tumor vascularity" can be a feature of left atrial thrombus as well as myxoma.

Cineangiography↗
PubMedDate not supplied

Pneumomediastinum revisited.

Pneumomediastinum may result from a variety of causes that may be either intrathoracic (eg, narrowed or plugged airway, straining against a closed glottis, blunt chest trauma, alveolar rupture) or extrathoracic (eg, sinus fracture, iatrogenic manipulation in dental extraction, perforation of a hollow viscus [corrected]. The radiographic signs of pneumomediastinum depend on the depiction of normal anatomic structures that are outlined by the air as it leaves the mediastinum. These signs include the thymic sail sign, "ring around the artery" sign, tubular artery sign, double bronchial wall sign, continuous diaphragm sign, and extrapleural sign. In distal esophageal rupture, air may migrate from the mediastinum into the pulmonary ligament. Pneumomediastinum may be difficult to differentiate from medial pneumothorax and pneumopericardium. Occasionally, normal anatomic structures (eg, major fissure, anterior junction line) may simulate air within the mediastinum. Iatrogenic entities that may simulate pneumomediastinum include helium in the balloon of an intraaortic assist device. In addition, pneumomediastinum may be simulated by the Mach band effect, which manifests as a region of lucency adjacent to structures with convex borders. The absence of an opaque line, which is typically seen in pneumomediastinum, can aid in differentiation. Computed tomographic (CT) digital radiography and conventional CT can also be helpful in establishing or confirming the diagnosis.

Adolescent↗